// SPDX-License-Identifier: GPL-2.0
/*
 * Functions corresponding to string type attributes under
 * HP_WMI_BIOS_STRING_GUID for use with hp-bioscfg driver.
 *
 * Copyright (c) 2022 HP Development Company, L.P.
 */

#include "bioscfg.h"

#define WMI_STRING_TYPE "HPBIOS_BIOSString"

GET_INSTANCE_ID(string);

static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
        int instance_id = get_string_instance_id(kobj);

        if (instance_id < 0)
                return -EIO;

        return  sysfs_emit(buf, "%s\n",
                         bioscfg_drv.string_data[instance_id].current_value);
}

/**
 * validate_string_input() -
 * Validate input of current_value against min and max lengths
 *
 * @instance_id: The instance on which input is validated
 * @buf: Input value
 */
static int validate_string_input(int instance_id, const char *buf)
{
        int in_len = strlen(buf);
        struct string_data *string_data = &bioscfg_drv.string_data[instance_id];

        /* BIOS treats it as a read only attribute */
        if (string_data->common.is_readonly)
                return -EIO;

        if (in_len < string_data->min_length || in_len > string_data->max_length)
                return -ERANGE;

        return 0;
}

static void update_string_value(int instance_id, char *attr_value)
{
        struct string_data *string_data = &bioscfg_drv.string_data[instance_id];

        /* Write settings to BIOS */
        strscpy(string_data->current_value, attr_value);
}

/*
 * ATTRIBUTE_S_COMMON_PROPERTY_SHOW(display_name_language_code, string);
 * static struct kobj_attribute string_display_langcode =
 *      __ATTR_RO(display_name_language_code);
 */

ATTRIBUTE_S_COMMON_PROPERTY_SHOW(display_name, string);
static struct kobj_attribute string_display_name =
        __ATTR_RO(display_name);

ATTRIBUTE_PROPERTY_STORE(current_value, string);
static struct kobj_attribute string_current_val =
        __ATTR_RW_MODE(current_value, 0644);

ATTRIBUTE_N_PROPERTY_SHOW(min_length, string);
static struct kobj_attribute string_min_length =
        __ATTR_RO(min_length);

ATTRIBUTE_N_PROPERTY_SHOW(max_length, string);
static struct kobj_attribute string_max_length =
        __ATTR_RO(max_length);

static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr,
                         char *buf)
{
        return sysfs_emit(buf, "string\n");
}

static struct kobj_attribute string_type =
        __ATTR_RO(type);

static struct attribute *string_attrs[] = {
        &common_display_langcode.attr,
        &string_display_name.attr,
        &string_current_val.attr,
        &string_min_length.attr,
        &string_max_length.attr,
        &string_type.attr,
        NULL
};

static const struct attribute_group string_attr_group = {
        .attrs = string_attrs,
};

int hp_alloc_string_data(void)
{
        bioscfg_drv.string_instances_count = hp_get_instance_count(HP_WMI_BIOS_STRING_GUID);
        bioscfg_drv.string_data = kzalloc_objs(*bioscfg_drv.string_data,
                                               bioscfg_drv.string_instances_count);
        if (!bioscfg_drv.string_data) {
                bioscfg_drv.string_instances_count = 0;
                return -ENOMEM;
        }
        return 0;
}

/* Expected Values types associated with each element */
static const acpi_object_type expected_string_types[] = {
        [NAME] = ACPI_TYPE_STRING,
        [VALUE] = ACPI_TYPE_STRING,
        [PATH] = ACPI_TYPE_STRING,
        [IS_READONLY] = ACPI_TYPE_INTEGER,
        [DISPLAY_IN_UI] = ACPI_TYPE_INTEGER,
        [REQUIRES_PHYSICAL_PRESENCE] = ACPI_TYPE_INTEGER,
        [SEQUENCE] = ACPI_TYPE_INTEGER,
        [PREREQUISITES_SIZE] = ACPI_TYPE_INTEGER,
        [PREREQUISITES] = ACPI_TYPE_STRING,
        [SECURITY_LEVEL] = ACPI_TYPE_INTEGER,
        [STR_MIN_LENGTH] = ACPI_TYPE_INTEGER,
        [STR_MAX_LENGTH] = ACPI_TYPE_INTEGER,
};

static int hp_populate_string_elements_from_package(union acpi_object *string_obj,
                                                    int string_obj_count,
                                                    int instance_id)
{
        char *str_value = NULL;
        int value_len;
        int ret = 0;
        u32 int_value = 0;
        int elem;
        int reqs;
        int eloc;
        int size;
        struct string_data *string_data = &bioscfg_drv.string_data[instance_id];

        if (!string_obj)
                return -EINVAL;

        for (elem = 1, eloc = 1; elem < string_obj_count; elem++, eloc++) {
                /* ONLY look at the first STRING_ELEM_CNT elements */
                if (eloc == STR_ELEM_CNT)
                        goto exit_string_package;

                switch (string_obj[elem].type) {
                case ACPI_TYPE_STRING:
                        if (elem != PREREQUISITES) {
                                ret = hp_convert_hexstr_to_str(string_obj[elem].string.pointer,
                                                               string_obj[elem].string.length,
                                                               &str_value, &value_len);

                                if (ret)
                                        continue;
                        }
                        break;
                case ACPI_TYPE_INTEGER:
                        int_value = (u32)string_obj[elem].integer.value;
                        break;
                default:
                        pr_warn("Unsupported object type [%d]\n", string_obj[elem].type);
                        continue;
                }

                /* Check that both expected and read object type match */
                if (expected_string_types[eloc] != string_obj[elem].type) {
                        pr_err("Error expected type %d for elem %d, but got type %d instead\n",
                               expected_string_types[eloc], elem, string_obj[elem].type);
                        kfree(str_value);
                        return -EIO;
                }

                /* Assign appropriate element value to corresponding field*/
                switch (eloc) {
                case VALUE:
                        strscpy(string_data->current_value, str_value);
                        break;
                case PATH:
                        strscpy(string_data->common.path, str_value);
                        break;
                case IS_READONLY:
                        string_data->common.is_readonly = int_value;
                        break;
                case DISPLAY_IN_UI:
                        string_data->common.display_in_ui = int_value;
                        break;
                case REQUIRES_PHYSICAL_PRESENCE:
                        string_data->common.requires_physical_presence = int_value;
                        break;
                case SEQUENCE:
                        string_data->common.sequence = int_value;
                        break;
                case PREREQUISITES_SIZE:
                        if (int_value > MAX_PREREQUISITES_SIZE) {
                                pr_warn("Prerequisites size value exceeded the maximum number of elements supported or data may be malformed\n");
                                int_value = MAX_PREREQUISITES_SIZE;
                        }
                        string_data->common.prerequisites_size = int_value;

                        /*
                         * This step is needed to keep the expected
                         * element list pointing to the right obj[elem].type
                         * when the size is zero. PREREQUISITES
                         * object is omitted by BIOS when the size is
                         * zero.
                         */
                        if (string_data->common.prerequisites_size == 0)
                                eloc++;
                        break;
                case PREREQUISITES:
                        size = min_t(u32, string_data->common.prerequisites_size,
                                     MAX_PREREQUISITES_SIZE);

                        for (reqs = 0; reqs < size; reqs++) {
                                if (elem + reqs >= string_obj_count) {
                                        pr_err("Error elem-objects package is too small\n");
                                        return -EINVAL;
                                }

                                ret = hp_convert_hexstr_to_str(string_obj[elem + reqs].string.pointer,
                                                               string_obj[elem + reqs].string.length,
                                                               &str_value, &value_len);

                                if (ret)
                                        continue;

                                strscpy(string_data->common.prerequisites[reqs], str_value);
                                kfree(str_value);
                                str_value = NULL;
                        }
                        break;

                case SECURITY_LEVEL:
                        string_data->common.security_level = int_value;
                        break;
                case STR_MIN_LENGTH:
                        string_data->min_length = int_value;
                        break;
                case STR_MAX_LENGTH:
                        string_data->max_length = int_value;
                        break;
                default:
                        pr_warn("Invalid element: %d found in String attribute or data may be malformed\n", elem);
                        break;
                }

                kfree(str_value);
                str_value = NULL;
        }

exit_string_package:
        kfree(str_value);
        return 0;
}

/**
 * hp_populate_string_package_data() -
 * Populate all properties of an instance under string attribute
 *
 * @string_obj: ACPI object with string data
 * @instance_id: The instance to enumerate
 * @attr_name_kobj: The parent kernel object
 */
int hp_populate_string_package_data(union acpi_object *string_obj,
                                    int instance_id,
                                    struct kobject *attr_name_kobj)
{
        struct string_data *string_data = &bioscfg_drv.string_data[instance_id];

        string_data->attr_name_kobj = attr_name_kobj;

        hp_populate_string_elements_from_package(string_obj,
                                                 string_obj->package.count,
                                                 instance_id);

        hp_update_attribute_permissions(string_data->common.is_readonly,
                                        &string_current_val);
        hp_friendly_user_name_update(string_data->common.path,
                                     attr_name_kobj->name,
                                     string_data->common.display_name,
                                     sizeof(string_data->common.display_name));
        return sysfs_create_group(attr_name_kobj, &string_attr_group);
}

static int hp_populate_string_elements_from_buffer(u8 *buffer_ptr, u32 *buffer_size,
                                                   int instance_id)
{
        int ret = 0;
        struct string_data *string_data = &bioscfg_drv.string_data[instance_id];

        /*
         * Only data relevant to this driver and its functionality is
         * read. BIOS defines the order in which each * element is
         * read. Element 0 data is not relevant to this
         * driver hence it is ignored. For clarity, all element names
         * (DISPLAY_IN_UI) which defines the order in which is read
         * and the name matches the variable where the data is stored.
         *
         * In earlier implementation, reported errors were ignored
         * causing the data to remain uninitialized. It is not
         * possible to determine if data read from BIOS is valid or
         * not. It is for this reason functions may return a error
         * without validating the data itself.
         */

        // VALUE:
        ret = hp_get_string_from_buffer(&buffer_ptr, buffer_size, string_data->current_value,
                                        sizeof(string_data->current_value));
        if (ret < 0)
                goto buffer_exit;

        // COMMON:
        ret = hp_get_common_data_from_buffer(&buffer_ptr, buffer_size, &string_data->common);
        if (ret < 0)
                goto buffer_exit;

        // STR_MIN_LENGTH:
        ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
                                         &string_data->min_length);
        if (ret < 0)
                goto buffer_exit;

        // STR_MAX_LENGTH:
        ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
                                         &string_data->max_length);

buffer_exit:

        return ret;
}

/**
 * hp_populate_string_buffer_data() -
 * Populate all properties of an instance under string attribute
 *
 * @buffer_ptr: Buffer pointer
 * @buffer_size: Buffer size
 * @instance_id: The instance to enumerate
 * @attr_name_kobj: The parent kernel object
 */
int hp_populate_string_buffer_data(u8 *buffer_ptr, u32 *buffer_size,
                                   int instance_id,
                                   struct kobject *attr_name_kobj)
{
        struct string_data *string_data = &bioscfg_drv.string_data[instance_id];
        int ret = 0;

        string_data->attr_name_kobj = attr_name_kobj;

        ret = hp_populate_string_elements_from_buffer(buffer_ptr, buffer_size,
                                                      instance_id);
        if (ret < 0)
                return ret;

        hp_update_attribute_permissions(string_data->common.is_readonly,
                                        &string_current_val);
        hp_friendly_user_name_update(string_data->common.path,
                                     attr_name_kobj->name,
                                     string_data->common.display_name,
                                     sizeof(string_data->common.display_name));

        return sysfs_create_group(attr_name_kobj, &string_attr_group);
}

/**
 * hp_exit_string_attributes() - Clear all attribute data
 *
 * Clears all data allocated for this group of attributes
 */
void hp_exit_string_attributes(void)
{
        int instance_id;

        for (instance_id = 0; instance_id < bioscfg_drv.string_instances_count;
             instance_id++) {
                struct kobject *attr_name_kobj =
                        bioscfg_drv.string_data[instance_id].attr_name_kobj;

                if (attr_name_kobj)
                        sysfs_remove_group(attr_name_kobj, &string_attr_group);
        }
        bioscfg_drv.string_instances_count = 0;

        kfree(bioscfg_drv.string_data);
        bioscfg_drv.string_data = NULL;
}